Thread and tube protector



Fell 8, 1955 R. A. PHILIPS THREAD AND TUBE PROTECTOR Filed May 29. 195oE INVENTOR Rnvfmond Phi lips BY i ATTORNEYS Z THREAD ANDr TUBE PROTECTORRaymond A. Philips, Cleveland, Ohio, assignor to Protctor Products Inc.,Cleveland, Ohio, a corporation o Ohio Application May 29, 1950, SerialNo. 164,980v

8 Claims. (Cl. 13S-96) This invention relates to protector caps forcovering andv protecting the plain or threaded ends of pipes, tubes, andthe like, while performing various operations thereon, and duringpacking, shipping, and handling of the same.

The'general object ot' the invention is to provide a new and improvedthread protector.

A more specific object or' the invention is to .produce a metal threadprotector having a soft lining held therein more securely than in priorart devices of this character.

Another specific object of the invention is to provide an 4improvedthread protector and liner assembly that may be formed with a singlestamping operation of a punch press or the like, whereby the assembly ofseparately formed metal shells and liners is eliminated.

Characteristic features of the method aspect of the invention are thesimultaneous severing of plates or discs of metal and liner materialfrom superposed sheets thereof and movement of severed metal and linerplates or discs together against a mandrel or stake, followed bypressing the twoy plates or discs together over the end of the mandrel,substantially without drawing the metal and 1n such manner as-to foldthe metal forming the sides of the resultingmetal shell and to lockcompressed portions of the liner between the folds of the metal.

The resulting thread protector,` in the form of a generally cylindricalmetal shell having one end open andv the other end closed, or partiallyclosed, is characterized by longitudinal folds in the side wall of theshell that begin at the open end thereof and terminate short of theclosed or partially closed end thereof. The thread protector is alsocharacterized by a liner that covers the interior surface of the metalshell and that is gathered or bunchedv between the folds in the sidewall of the metal shell so as to be securely held against removal orslippage with respect to the metal shell.

Further objects, advantages and features of the invention will becomeapparent from the following more detailed description of an illustrativeform of the device and a' preferred method of making the same, and fromvthe accompanying drawing in which- Figure 1 is a plan viewyof thethreaded end of a length of pipe with a thread protector embodying thepresent invention applied thereto, portions of the thread protectork andpipe being broken away to show the interior construction of the threadprotector and its relationship with the pipe;

Fig. 2 is an end elevation of the thread protector shown in Fig. l,looking at the open end thereof with the pipe removed.

Fig. 3 is a fragmentary longitudinal section through the threadprotector of Figures l and 2, the plane of the section being indicatedby the line 3-3 in Fig. 2; and

Fig. 4 is a vertical section through a die and punch assembly forforming thread protectors of the type il lustrated in Figures 1 to 3 andshowing sheets of metal and lining materials in. position for stampingblanks therefrom and showing folded blanks of the metal and liningmaterials as they appear in the die assembly at the conclusion of theforming operation.

Referring first to Fig. 1 the protector cap of the invention preferablycomprises a generally cup-shaped metal shell 10, entirely open at oneend and at least partially closed at' the opposite end by a radiallyinwardly directed end wall 11. The end wall 11, in this instance, isshown as having a large aperture therethrough so that this wall, ineffect, takes the form of an inwardly directed annular ange. f

Completely covering the interior surface of the shell 10,v including theinterior of the end wall 11, is a liner 12 that is preferably formedfrom a relatively soft, compressible or deformable, and substantiallyinelastic sheet material, such as kraft paper, paperboard, a plasticfilm, sheet lead, sheet aluminum, or the like. This liner is preferablysufficiently soft to permit the shell to be forced over the threaded endof a pipe 13.

This composite cap of metal and soft lining material is preferablyformed from at sheets in a single stamping operation, ask hereinaftermore fully described. The manner in which this stamping operation isperformed avoids any substantial drawing of the metal and shapes'r theflat sheet materials by folding them as they are drawn snugly around'thesides of the mandrel or stake of a suitable die assembly. As best shownin Figs.,1 and 2, the folds.14` begin at the open end of the cap andextend in an axial direction inthe side wall thereof, terminating shortof the closed or partially closed end of the cap. Because ofthesymmetryfof the forming mechanism, there is generally some semblancevof regularity in the size, shape, and spacing of the folds 14, butprecise regularity is not particularly sought.

The nature of the individual folds 14 may best be described as doublereverse bends. Considering any one of these double reverse folds, asviewed in Fig. 2, an outermost cylindrically curved metal portion 16 isfirst reversely bent back upon itself to form an intermediate foldsection 17, which is then bent back upon itself a second time to form aninnermost cylindrical portion 18. n

Now, considering the next adjacent double reverse foldA ineitherdirection from the one first considered, it will be observed that it isformed in the same manner as the first but that each bend is directedoppositely tothe corresponding bend in the'first, folding of alternatedouble reverse bends around the cap are the same and the folding of theintermediate double v reverse bends is in opposite directions.

The lining material 12 is somewhat similarly folded, to a degree, butthe folding of the liner is generally so Virregular as to present noclearly discernible repeating pattern. In the course of the foldingoperation, the nonresilient, soft and compressible lining material isforced to conform to the interior contour of the metal shell, beinghunched or gathered in a rather highly compressed condition into all ofthe spaces between adjacent vfolds of the metal shell. The interiorsurface of the liner is relatively smooth and is more accuratelycylindrical than either surface of the folded metal shell, -but iscovered with an irregular pattern of tightly compressed creasespredominantly running generaly axially thereof and producing only slightsurface indentations and ridges, ras indicated in Fig. 3.

The packing of the substantially non-resilient lining material tightlyinto the spaces between folds of the metal shell causes the liner `to befirmly gripped thereby and held in place.

hesive between the metal and the liner.

The finished cap should be somewhat larger in its inl-i side 4diameterat the open end thereof than at the opposite end to produce a taper moreor less conforming tothe normal taper of pipe threads.

metal shell. The rigidity of the cap is increased by the longitudinallyextending folds in the cylindrical side wall of the shell, and thesereinforcing foods contribute materially to the force with which the capgrips the end of a pipe or tube to which it is applied.

According to the invention, the above described cap -and the linerforming a part thereof are formed in their assembled relationship by asingle stamping operation. Suitable stamping tools for this operationessentially comprise a die 21 having a cylindrical opening 22 therein;an

annular punch 23 having cylindrical inner and outer conii-'tours andadapted to move into the cylindrical die open vPatented Feb. 8,11955Thus, the directions of v However, if desired, this gripping action maybe supplemented by the use of a thin layer of :id-.1

This taper may be contlnuous from end to end of the cap or may start ata ing 22`with small"cle`arance` for shearing discs from sheetmaterial-passed-betweenthe-dieandthe-punch;a-tapeied` generallycylindrical stake or Amandrel 24 concentrically disposed within the dieopening 22 with the upper end of tliewmandrel disposed slightly below;the upperwend'lof the-*die :opening 22'; and an iinner punch .'26:concentrically mounted=withiri'thefffirstiimentioned,V p unchl':y Inthe. eventi. vra cap :havin g f acompletely Iclosed i end is desired,the :inner punch ,26fmay-be1ornittediand. the mandi-ell 24eywhic'hfis'lshown withfafcentral borewZf'-'for accommodatingthe'inner-punch26, -maybe made as-a;solid lpiecez.

These tools may be-'assembled upon la base 343;,7 the mandrel 24-beingoutwardly- 1 flanged.' at its lower Aend' to provide al seati f31frfforr the die 2liL The seat 1.31:'fis; =pro t vided withfa pa-ir ofapertures'- 32 at` diametrically opposite,` v pointslfor accommodating ap luralityof pins `33 imountedi therein for vertical'lslidingmovementandpreferably. urged upwardly lint a well'knoww manner fby suitable Isprings orf hydraulic oushioningmeans; (not shown).- The upper ends=fof=the lpins 33 V"bear-,against an ejecting ring Vv311i thatis=- disposedzwithinv the die 21'y and surroiindsf'the` mandrel' 24-witha-fieesliding'iit; The ejecting ring v3141is normally. urged upwardlybythe-Springactuated pins 33 andv is heldfwithan'lannular shoulder3i6l`on^fthev ejeeting ring-y inengagement".withY an` interiorannulareshoulder 37 l of theidief- 21;

The outer contourof .the mandrela24-is-icylindr`ical overy mostofits=lengthfbut"tapers'from a point to -the upper end'thereofftoprovidesubstantially greater clearance betweenthe*y mandrel andthe innervcylindricall surfaceof the punch 23\"at the -upper end ofl the mandrelthan-below'the poir'it38 whereithe taperbegins 1 The=innerpunch 26 andtheouter punch `23 are rigidly mountedy for movement together, and asleeve 41'isA slidably mounted. around the inner` punch 26` andvinsidethe outer punch 231 Thefsleeve41"is-normallyheld'downwardlyiwithzits lowerend: even; withthe lowerendof the outerpunch-ZS in any/suitablel manner, las lbya springor"hydr'auliccontr.ol ('not shown),- so that'thesleeve4'1 engages` the'.work' at: the same .time as the louter punch 23 and movesitherewith`duringthe-i'rst punchingvoperation `and until punched i discs. arecarriedV1 downwardly against. the end kof thefmandrel 24. The sleeve41`is.then stopped andserves' to holdthe punched discs rmly inV placetagainstthemandrel during the remainder of 'the punchingandlformingoperation.

metal sheetf43ffand'- a sheet oflining material 44` disp'osed'togetherin` superposed .relationshipare yfedi over th'ewdi'e opening 22. Thesesheetsmaybe adhered; to-

gether byia.. suitable adhesive or may be merelyv fed .to-

gether. asrdesi'red. When the punchassembly is lowered, theouter punch,v23 severs-.di'scs.;from themetalsheet 43"` and the liner sheet441simultaneously,.and the outer punch 23' and sleeve 441 'move thesevered. discsdownwardly. onto the mandrell 24 vwhile'the die 212maintains the discs in registry: The 'sleeve 41exerts a constantdownwardpressure against the discs opposite the periphery ofl the upper end'ofthe mandrel as the downward movement ofthe. outer die 23 "is continuedtoV the lowermost position, illuS- trated in Fig. 4; DuringA they latterpart of this move,- menttheinner punch 26'punches an aperturethroughbothof "the discs, and the severed blanks drop downwardly through the hollowmandrel and out of the die` assembly. Iii'the'eventyan aperture.. intheend ofthe cap isnot desired',- a solidimandreliis employed and the innerpunch 26 'is omitted. In this case, a. solid rodis preferablysubstituted' for the 'sleeve 41V so that the pressure applied to themetal sheet thereby will' be applied `entirely over the upper endofthezmandreli The^minmum-cl`earance"between the outer punch 23 and; the"mandrel 24` below the. tapered portion of the mandrel should beat leastthree. times the' initial thickness'of the metal sheet 431 The-clearanceabovethe point 38fwhere the taper-ofthe mandrel begins; is substantiallygreater lthan the' minimum gclearance, as. illustratedin Fig. 4: Withthis large-'clearancebetween theouter punch 23- andthe mandrel y241,little drawing'of the discs is -effected as they are formed over themandrel 24. Since'the forceexerted-upon` the upper surfaceofl themetaldiscy by the outer; A'punch 23 is vsubstantially uniformlyV distributedlentir'el'y around? its periphery throughout the forming ope-ra tion;the' metal tends toxfold in th'ef'manner"describedv` above-andl shownin:Figures: l-and 2, andthe lower edges: 4'and'f4f'of theresulting-capa'lie-almostfinthesame plane. The l'owerfinnenedgefoff-'the *punch 21tr-isf:preferablyvv rounded, as shown at 49,to slide smoothly over the metal being Vformedasth'e"direction of'tl'ieforce ofthe die on the metal being formed is directed more and more in aradially inward direction as the rounded edge of the punch passesdownwardly over and beyond the periphery of the partially formed cap.

As long as the minimumclea-rance between the outer punch 23andthemandrel24,below the Ataperiofthe mandrel does not exceed'threetimes the initial'thickness of themetal sheet-,43,v theu folds; in the`,.sidesof, tlregmeta-15,1h

s hell will,be ,tightly/creas ed,-.` as 'shown in Eig-2g anllthe liningmaterial will be tightly packed and compressedso as to completely fillthe spaces between adjacent folds in the metalshell;

The clearance between the inner punch 26 and the bore 27 of themandrel"24iis'fpreferablyslightly greater than that required to producea clean shearing cut. As a result, the inner edge of the ange 11 of themetal shell is-:turneddo'wnwardlyover-the adjacent Yedgeofthe liner, yas-v showfnat..48.^` ThisA provides Ianv additional"'barrierl againstYslippage-of-therliner :withinF the meta-l shellf? Where ranaperti-ireinthe: endofl the cap Ais desired; 'the diameterfof Cthealiierture ispreferably'.y `selectedslightly e larger than the interiordiametreoffthe *pipe* to which' the" cap vis'to lbe'applie'drv Thisprevents the-cap from obstructingfthe-interioif-boie ofthe pipe to anydegree andlpermits. various^operatioiis to 'beperformed upon'theinterior of" thepipefafterit-has.been `threadedand the capA hjasbeeriapplied over the threads;

Uponwithdrawal of* the punch assembly fromthediey 21,- thee1ectorrring34follows the punch23upwardly until theshoulder '36 of theA ring engagesthe. shoulder 3T of'thedie.' During-upward movementjof'the ring '.i'lityengages the flower edge 46v ofthe metalshell" of theA cap and lifts thecap upwardly` Oithe m andre.l"24.A Thisk frees the finished 1'cap soVthatitcaribet lifted "o ut ofthe die'21feither manually ormechanically, Aas desired.'

The' particular embodimentsofthe invention shown and described in,detailihereininvolve caps ,having theI generalilshape,` of; a circularcylinder vvthat is, 'formed'L from z discs (circular plates)of"metaLandjjlinitig material. Itf will be apparent, however,thatcapshaving ovalgipolygonal,` or other cross-sectional outlines,l may readilybe. formediin the same .manner from,..appropria1tely shaped,

plates ofmetal vand'liningmaterial; Suchother shapes.

are desirable for applicationloithe endsl of correspondinglyshapedrods,tubesand the jlike.- A

Accordingly, ini this specification. andin the ,appended glaims, unless.the kconteiitotherwiserequires the vterm cylindrical, is intended'L tolbe construedin its: broad` geometricalsense and to cover the variousshapesgemV erated by a straight linegeneratrix as. it moves,normal` toitself along'k av closedlpath;whether oval,- elliptical, polygonaL: orirregularA inoutline.

The ythread protectors .manufacturedinaccordance, with:

the`.present invention may be applied overthecnds ofI either threaded orUnthreaded 'pip,e,s, rods,l tubesor. the

like,` andiwillrmly. grip the ySameandbe retainedLsecurelythereon.VThey. may. beiappliedina simpleiman-l-- ner. by merely jamming them overthe. ends of: members Atobeprotected, either manually, preferablyusinggamallet pending application, Serial No. 85,580, ledAprilS, 1949,`

for a Thread and Tube Protector, now abandoned;

Havingrdescribed, my invention, I ,claim;

l. AA thread protectory comprisingl an outerl cup-shapedg. metal .capofgenerally cylindrical .for.m;havingf;a ,plug

rality ofi double :reverse folds', in the side walll 4thereof. spaced.circumferentially 'around-.the cap; and extending.

longitudinally' thereof, anda a; continuousl liner of ,a rela'- tivelysoft sheet material covering the inner- .;surfaceroh.

said cap and having portions bunched between and tightly gripped byadjacent pairs of said folds.

2. A thread protector comprising an outer cup-shaped metal cap ofgenerally cylindrical form having a plurality of double reverse folds inthe side wall thereof spaced circumferentially around the cap andextending longitudinally thereof, and a continuous liner of a relativelysoft sheet material covering the inner surface of said cap and havingportions bunched between and tightly gripped by adjacent pairs of saidfolds, the side wall of said cap adjacent the closed end thereof beingtapered toward said closed end.

3. A thread protector comprising a generally cylindrical metal shellhaving one end open and the opposite end partially closed by a flangeextending radially inwardly, the generally cylindrical wall of saidshell having a plurality of axially extending double reverse foldstherein, said folds beginning at the open end thereof and terminatingshort of the partially closed end thereof, and a continuous liner of arelatively soft sheet material covering the interior surface of saidmetal shell and being bunched between and tightly gripped by adjacentpairs of said folds.

4. A thread protector comprising a generally cylindrical metal shellhaving one end open and the opposite end partially closed by a flangeextending radially inwardly, the generally cylindrical wall of saidshell having a plurality of axially extending double reverse foldstherein, said folds beginning at the open end thereof and terminatingshort of the partially closed end thereof, and a continuous liner of arelatively soft sheet material covering the interior surface of saidmetal shell and being bunched between and tightly gripped by adjacentpairs of said folds, said ange having an inner edge turned inwardly inan axial direction over the adjacent edge of said liner. y

5. A thread protector comprising a generally cylindrical metal shellhaving one end open and the opposite end partially closed by a angeextending radially inwardly, the generally cylindrical wall of saidshell having a plurality of axially extending double reverse foldstherein, said folds beginning at the open end thereof and terminatingshort of the partially closed end thereof, and a continuous liner of arelatively soft sheet material covering the interior surface of saidmetal shell and being bunched between and tightly gripped by adjacentpairs of said folds, the generally cylindrical wall of said shell beingtapered for a portion of its length adjacent and toward the partiallyclosed end thereof.

6. A thread protector comprising a generally cylindrical metal shellhaving one end open and the oppositie end partially closed by a iiangeextending radially inwardly, the generally cylindrical wall of saidshell having a plurality of axially extending double reverse foldstherein, said folds beginning at the open end thereof and terminatingshort of the partially closed end thereof, and a continuous liner of arelatively soft sheet material covering the interior surface of saidmetal shell and being bunched between and tightly gripped by adjacentpairs of said folds, the generally cylindrical shell, adjacent thepartially closed end thereof, being tapered inwardly toward said ange,and said flange having an inner edge turned inwardly in an axialdirection over the adjacent edge of said liner.

7. A thread protector comprising a generally cylindrical metal shellthat is substantially circular in cross section and is at leastpartially closed at one end by a radially inwardly extending wall andopen at the opposite end, the generally cylindrical wall beinglongitudinally folded into tightly creased double reverse folds at aplurality of locations spaced around the circumference thereof,alternate ones of said double reverse folds beginning with a fold underand circumferentially back in one direction, and the remainder beginningwith a fold under and circumferentially back in the opposite direction,and a continuous liner of relatively soft sheet material covering theinner surface of said shell and adhered thereto, said liner beingbunched into compressed portions filling the interior spaces betweenadjacent oppositely bent folded portions of the shell and being tightlygripped thereby.

8. The thread protector of claim 1 in which said liner is adhered tosaid metal shell.

References Cited in the iile of this patent UNITED STATES PATENTS

